Typically, electrical junction boxes that are mounted within an engine compartment of a vehicle often include: a connecting components such as a wiring harness; electronic components such as relays, fuses, or the like; and electric equipment such as an electric control unit. Therefore, when a vehicle is operating in the rain, or when an engine compartment is washed under high pressure, it is necessary to prevent water from being splashed onto an inside of the electrical junction box. Therefore, these electrical junction boxes are waterproofed by providing respectively waterproof structures to a box main body receiving the electric components and the like, and to a cover covering an upper opening of the box main body. As such, the electrical junction box is a waterproof box.
Regarding the waterproof box, it is known that these waterproof boxes may be waterproofed by for example providing a packing between the waterproof structure portion of the box main body and the waterproof structure portion of the cover (for example, see Patent Document 1 listed below), or alternatively by overlapping the waterproof structure portion of the box main body with the waterproof structure portion of the cover without using any packing (for example, see Patent Document 2 listed below).
When using the packing, a gap is filled with the packing material that is disposed between both waterproof structure portions, thereby increasing the waterproofing performance. However, the number of components in this solution is increased due to the packing, and the cost of the waterproof box is increased due to the packing. Further, the man-hours for attaching the packing are increased as well. Therefore, in recent years, a packing-less type of waterproof box has been used.
As a packing-less type of waterproof box, a waterproof box disclosed in the Patent Document 2 includes: a box main body having an upper opening; and a cover covering the upper opening. This waterproof box is waterproofed by overlapping the waterproof structure portion of the box main body with the waterproof structure portion provided on a seam joint portion of the cover. Specifically, the waterproof structure portion at the box main body side includes a circular waterproof convex portion provided around an edge of a peripheral wall of the box main body. The waterproof structure portion at the cover side includes a circular waterproof concave portion provided around an edge of a peripheral wall of the cover.
According to the above configuration and the above structure, when the cover is disposed above the upper opening of the box main body, then moved straight downward, and the waterproof structure portions are overlapped with each other, the waterproof convex portion is inserted into the waterproof concave portion. Further, a U-shaped cover lock provided on the waterproof structure portion of the cover is caught by, and locked with a main body lock provided on the waterproof structure portion of the main body. As such, the box main body and the cover are in a locked state. The main body locks and the cover locks are arranged on at least two positions on left and right sides of the waterproof box (or front and rear sides). These two positions are separated from each other.